PAGGES Engineering1015 Central Parkway SouthS.A., TX 78232www.paggesengineering.weebly.com

January 6, 2013

ASTU Investors 2100 Network Dr, Suite 100San Antonio, TX 78249-3966

RE: Preliminary Geotechnical Engineering Study5681 Utex Blvd.San Antonio, Texas

PAGGES Engineering (PAGGES) is pleased submit our Geotechnical Engineering Study for the above referenced project. The purpose of this study was to preliminarily characterize the subsurface conditions of the site and prepare a foundation analyses for the proposed building

The following report contains our design recommendations and considerations based on our current understanding of the project information provided to us. There may be alternatives for the foundation system, and PAGGES recommends that a meeting be held with ASTU investors and our design team to discuss these alternatives.

We appreciate the opportunity to service you on this project. If you have any questions about this report please contact us.

Thanks,

PAGGES Engineering

Eric PannabeckerSenior Geotechnical Consultant

Introduction

PAGGES Engineering (PAGGES) has completed preliminary characterizing the subsurface of the site and foundation analyses of the proposed building on site located to the north side of Utex Blvd. in San Antonio, Texas. This report presents our findings from site visits and the use of soil mapping software (Web Soil Survey) provided by the United States Department of Agriculture in conjunction with National Resources Conservation Service.

Laboratory Testing

During the initial site visit on February 2, 2013 soil samples were extracted and sent to the lab. Once the various tests on the samples are completed the information will be used to verify the soil parameters given by Web Soil Survey for the area of interest. The estimated values given by Web Soil Survey are shown in the Appendix.

General Site Conditions

Site Description

The 3 acre site is located approximately 1000 ft. to the East of Leon Creek at 5681 Utex Blvd. in San Antonio, Texas. Leon Creek is a natural dry creek bed that is used as a drainage channel during periods of rainfall. The land has previously been cleared of most of the large oak trees to serve as a cow pasture. There are predominantly mesquite trees on site. There are no existing structures onsite. The topography generally slopes from north to south at 1-3 percent slopes. This slope favors the use of the existing channel running along East to West on Utex Blvd. There is a site location map shown in the Appendix.

Subsurface Profile

The soil on site has been transported by water in the creek and deposited overtime to form the Lewisville Silty Clay layer on the banks of the creek. This dark brown clay is underlain by a layer of solid rock called Edwards limestone. This limestone is generally considered hard throughout with harder areas of chert and dolomite dispersed randomly. The depth to the limestone layer varies from 5-20 ft. throughout the region.

Groundwater

This area is generally known to have a water table depth of 15 ft. but at this time Central Texas is experiencing a drought which has influenced the groundwater levels. Therefore, groundwater levels at this time could be lower than usual. Groundwater will most likely be located at the clay/limestone interface which varies from 5-20 ft. Fluctuations in the groundwater levels will occur due to variation in rainfall and surface water run-off.

Foundation Analyses

Expansive Soil-Related Movements

The Lewisville Silty Clay on site is known to have shrink/swell characteristics. The Texas Department of Transportation (TxDOT) Tex-124-E, Method for Determining Potential Vertical Rise (PVR) will be used to estimate the potential upheaval pressure for a slab on grade. This method is based on empirical correlations using the plasticity index of the soil and the assumption of moisture content fluctuations with the seasons. PVR values of 1-3 in. are expected for this soil type.

Overexcavation and Select Fill

In order to minimize the slabs on grade from expansive soil related movements we recommend excavating the dark brown clays within the building footprint to a depth of 5 ft. or to the top of the limestone layer. The select fill for the building area should be chosen to maintain negligible PVR values for the slabs on grade.

Drainage Considerations

When overexcavation and select fill replacement is used to minimize the expansive soil related movements, drainage during and after construction can be crucial. Water that enters the select fill during construction can cause problems with compaction and increased access to moisture after construction.

There are numerous methods for surface and subsurface drainage during and after construction that will minimize the swelling and shrinking of the soil. Some but not all of the methods are discussed here after. Berms can be installed on the uphill side of the construction area to divert surface runoff away from the excavation area. By sloping the surface of the subgrade by a minimum of 1.5 percent to the drainage channel will reduce the amount of water retained in the ground. During compaction of the select fill you can maintain a slope after each fill to increase runoff of water away from the building footprint. The details to each of these methods as well as alternatives can be discussed during the proposed meeting.

Appendix

Site Location MapSan Antonio Children’s Art Museum

5681 Utex BlvdSan Antonio, Tx 78249

Lewisville Silty Clay Characteristics(General Characteristics from Web Soil Survey)

Percent Clay=47.9%Percent Sand=7.9%Percent Silt=51.1%

USC Group: CLAASHTO Group: A-7-6

Atterburg Limits:Liquid Limit=47.9%Plastic Limit=20%Plasticity Index=27.9%

Internal Angle of Friction=27 +or- 4 degrees

Cohesion=20 +or- 10 kPa